Method of and apparatus for concentrating acid



I. HECHEBLEIKNER AND T. C. OLIVER.

METHOD 0F AND APPARATUS FOR COVNCENRATlNG ACID. APPLICATION FILED SEPT. 16, |920.

1,41 5,443. Patented May 9, 1922.

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lilllu l. HCHENBLEIKNER AND T. C. OUVER.

METHOD 0F AND APPARATUS FOR CONCENTRATING ACID.

APPLICATION FIL-ED SEPT. 16. 1920.

1,415,443. Patented 9,1922.

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UNITED STATES PATENT OFFICE.

INGENUIN HECHENBLEIKNER AND THOMAS C. OLIVER, or CHARLOTTE, NORTH CAROLINA, AssIGNoRs To CHEMICAL CoNsTRUCI'IoN COMPANY, A CORPO-RA- TION OF NORTH CAROIIIIINAA METHOD OF AND APPARATUS FOR CONCENTRATING CID.

Specification of Letters Patent.

Patented May 9, 1922.

Application filed September 16, 1920. Serial No. 410,626.

To all whom t may concern:

Be it known that We, INGENUIN HECHEN- ELEIKNER and THOMAS C. OLIVER, citizens of the United States, and residents of the city of Charlotte, in the county of Mecklenburg and State of North Carolina, have invented certain new vand useful Improvements in --Methods of and Apparatus for Concentra in Acid, of which the following is a specication.

This invention relates to a method of and apparatus for treating acid.

In the present ,instance We have shown and described our invention as' employed for the concentration, recovery and restoration of the sludge acid resulting from the treatment of petroleum oils With sulphuric acid in well known relining processes, but Wel Wish it to be understood that our invention is not limited in its useful purpose to the treatment of sludge. acid as it Will be found adapted for the concentration and purification of other liquids and acids with obvious variations and changes to suit the particular conditions encounted.

' As is well known, crude petroleum oil or its fractional distillates is refined by subjecting the same to the action of sulphuric acid so that the latter Will absorb the heavy hydrocarbons and other undesirable elements present in the crude oil. In practice, the sulphuric acidv so used has an initial strength of about 66- degrees -Baum or stronger, but at the completion of the operation, and after the refined oil has been separated, there'remains a sludge or Waste or spent acid, which .not only contains the impurities removed from the oil, but is also of a'reduced strength, usually about 50 degrees Baume, due to the fact the acid has absorbed a certain amount of water during the refining process.N This sludge acid is generally then subjected to further dilution Withsteam and Water-in the operation of recovering such oil as may remain therein,

and for the purpose' of relieving the acid,

as much as possible, of its absorbed impurties. This secondary treatment results in further diluting the acid and reducing it to a strength of usually about 30'y degrees Baume, and there also remains in the body of acid a considerable amount of hydrocarbon containing volatile impurities. vTherefore. in order to reclaim or'recover the sulphuric acid from the sludge and render it fit for further use in the refining of oil, it is not only necessary to concentrate the acid for the purpose of eliminating Water and thereby raising or restoring the acid to its eicient Working strength of about 66 degrecs Baume, but it is the undesirable hydrocarbons remaining in the acid be broken up, and the volatile impurities thereof be driven off, so that with the removal of such volatile impurities fore1gn matter remaining in the acid will be principally in the nature of inert carbon Whichis incapable of effecting or ,reducing the eficiency of the reclaimedx sulphuric acid when the latter is subsequently again used in the refining of oil.

Heretofore the conventional and generally practiced method of recovering, reclaiming and concentrating sludge acid has been to run the sludge into a suitable still or container and subject the same to external heat until the desired temperature and strength plication of internal heat, this being accom plished by passing hot air or hot gases directly through vthe acid.

In using this internal heat treatment for the reclaimlng and concentration of sludge acid we have found certain defects incident thereto, the principal difficulty. appearing .to be that the acid is not subjected to suicient heat because of the fact that the violent agitation set up by the air or gases passing through the acid causes a cooling of the latter and prevents the temperature of the acid reaching a point above from 400 to further required that 450 degrees F. This comparatively low temperature -is insuicient to break up the objectionable hydrocarbons and to elimin.

ate the volatile impurities thereof, so that `undesirable components are ,still present when the acid has been concentrated to its desired strength. We have discovered however that if the body of sludge acid can' be internally heated to a temperature of from 540 to 560 degrees F., for a substantial period of time, say from-one to six hours, the volatile impurities will be driven off and the undesirable hydrocarbons either eliminated entirely or reduced to substantially inert carbon which is incapable' of affecting the efi'ciency of the acid when again' yused for -oil refining purposes.

In the practice of our invention We proceed according to such a method and through the instrumentality of such an apparatus that not only is the diluted., weak, spent acid concentrated and restored to its desired strength of say 66 degrees Baume, but'the deleterious impurities hereinbefore mentioned are eliminated or rendered ineffective. All this we' accomplish with far greater rapidity7 economy, efficiency and convenience then is possible by previously known methods andl equipment.

Before entering into a detailed descriptio of our invention we will brieHy state that the preferred form of apparatus which we section forming an extension of the concentrating section. The acid coming down the tower passes first into the concentrating section of the flue, where it is agitated -and concentrated at a relatively low temperature and-thence Hows to the purifying section of the Hue wherethe. undesirable impurities are eliminated while the acid is in a non-agitated or static condition by the application of heat at a'relatively high temperature. VFor the purpose ofboth concentration and puri- Hcation we resort to the use of a heater which is submerged in the acid within both y sections of the Hue, and through which heater a suitable heating agent such as hot air or hot gas is passed under pressure. The heating agent is admitted, preferably at a temperature offrom 1150 to 1350 degrees F., to that portion of the heater which is located within the purifying section of the Hue, and conditions are so regulated that in its passage such air or gas will heat the concentrated static body of acid to a temperature of 550 degrees F., or thereabouts, or sutlicient to break up the undesirable hydrocarbons and to drive off the volatile impurities. The heater in this section of the Hue acts as a heat exchanger and the air orV gas naturally loses a portion of its heat units, so that after heating the static acid it passes into the portion of the heater located within the concentrating section of the Hue at a somewhat lower temperature than at its point of entry to the heater. The portion ofl the heater within the concentrating section .of the ,Hue is provided 'with suitable passages through which the air or gas issues, under pressure, in the form of jets or streams, and

This agitation results in all portions of the acid being presented for direct contact with the hot gases and consequently the -water will be rapidly eliminated and concentration quickly effected. Furthermore, it will result in concentration being accomplished at a lower temperature than were the acid subjected to the hot gas while in a static condition, for experience has shown that while the static body of acid will require to be raised to a temperature of over 500 degrees F., for proper concentration,-in anv agitated condition the concentration will proceed at a temperature of approximately 400 degrees F. The heated gases after passing through'the body of acid enter the tower in an up-Howing stream,r thus meeting vthe down-flowing stream of weak acid, and as the gases still retain a slight portion of their heat the down-coming acid will be preheated, thus adding to the efficiency of the concentrating operation. In practicing our invention it is not our intention to boil Lthe acid in the purifying section of the Hue in a pronounced manner, but to heat the acid sufficiently to cause it t0 simmer or stew at or slightly below its boiling point.

Our invention consists in the method of treating acids, and in the apparatus set forth in and falling within the scope of the appended claims. Y

In the accompanying drawings: Y Figure 1 is a view partly in side eleva-tio and partly in section of a preferred form of apparatus embodying our invention, A

Figure 2 is a View partly in plan and partly in horizontal section,

Figure 3 is a cross s tional view the line 3 3 of Figure; 1,

Figure 4 is a similar view 'taken on'the line4-4ofFigure 1. .j Y j i Referring now to the accompanying drawings in detail the letter A indicates the taken on `foundation, which may be of any suitable character, and is preferably constructed lof concrete or similar material and may be revided adjacentits top portion with a series of ports or openings 4'thro`ugh which the acid or other liquid may pass from the compartment C', which is the concentrating section of the flue, to the compartment P, which is the purifying section of such flue, these openings or ports being preferably located a slight distance below the normal liquid level. The concentrating section of the flue communicates with the'bottom portion of the absorption tower T. This tower may be of any well known construction and in the present instance is provided at its lower portion with spaced arches 5, of acidproof brick set in acid-proof cement, and designed to support a bridge 6, corr posed of parallel rows of bricks, the bridge in turn sustaining the brick checker work 7 above which is arran ed the usual quarts for filling shown at 8. Such packing may be used as will suit the particular oil undergoing treatment, and in some instances the packing may be omitted entirely. At .its upper top the tower is provided with the usual acid-spraying inlet pipe indicated at 9,' and an outlet pipe 10, for the escape of spent gases. As is usual, the weak, spent acid to be concentrated and purified is introduced into the top of the tower through the acid inlet pipe 9 and trickling down over and through the packing and' the checker work, passes first into the concenvtrating section C, of the acid flue, and when the proper level has been reached flows through the ports 4 in the flue partition, and into the purifying section of vsuch flue.

In order to internally heat the acid for the purpose of concentration and purification we employ a suitable heater, and in the present instance such heater which is indicated as an entirety by the letter H, comprises a pair of parallel, horizontally disposed pipes 11, also of .acid-resisting material, extending substantially the length of the acid flue, the inner ends of these heater pipes being supported in oie of the walls of the tower as at 12, while the outer ends of said heater pipes are supported in the wall 13, at thedischarge end or pan of the acid flue 14. Mounted on the floor of the acid lue at suitable spaced intervals are acid-resisting blocks 15 which act to support the heater pipes.

It will be noted that the heater pipes extend throughout both concentrating and,

latter.

purifying sections of the acid flue, and such pipes are provided substantially throughout their length with spaced perforations -or openings 16 forming ports for the escape of the hot air or hot gas under pressure. However, the ports formed in the portions of the heater pipes lying within the purifying section of the acid flue are normally closed by means of suitable and removable caps or.

seals 17,-so that as the heating medium, such as the hot air or gas p asses through those portions of the pipes lying within the purifying section of the flue, it will not escape into the acid, but will merely serve to heat the latter, while when such heating medium reaches the perforated portions of the pipes lying within the concentrating section of the flue it will escape under pressure through the openings or ports and be projected into the acid in such flue section, thereby agitating and concentrating such acid. The hot air or gas may be supplied to the pipes 11 through any suitable arrangement of lues or conduits. In the present instancewe show a main heat conduit 18, connected with a suitable source of heat supply, such as a'furnace (not shown), this conduit 18 extending transversely above the apparatus and being connected with the outer end portion of each heater pipe 11, by meansof a vertical branch pipe 19, these branch pipes extending down through the roof of the acid flue. A suitable valve, conventionally illustrated at 20, is provided for each branch pipe 19, in order to turnon o-' cut off the supply of heating medium from each of thehorizontal heater pipes, as will be readily understood. The discharge pan 14 of the acid flue is provided with a suitably arranged draw-oill or discharge pipe 21, through which the strong or concentrated and puriedacid may be withdrawn from the flue, while the opposite end of the acid flue, or that end adjacent the' y tower is provided with a -suitably packed drain pipe 22 for the purpose of draining down through the tower ows'into the con- 'centrating section of the flue. The heating medium having been admitted, under pressure, to the horizontal heater pipes 1.1,v flows through the latter toward the tower and is discharged through the open ports 15 into the concentrating section of the flue in the form of jets or streams, and passing-up through the acid, agitates the latter, tossing the body of acid so that all parts of the latter will be presented to heat action and consequently the water willl be rapidly driven off with vthe resulting concentration of the acid and without material loss of the ports 4 in the-'partition or baille wall, it flows into the purifying section of the flue. Here,'

not being subjected to agitation. by the air or, gas it will assume a substantially static When the level of the acid inthe l lconcentrating section of the flue reaches the temperature, say frm 11'50 to i350 degrees F., and this high degree of heat Will rapidly the undesirable hydrocarbons and to drive off the Volatile impurities of the latter, this usually taking` place at a temperature of from 540 to 560 degreesvF., or thereabouts. The hot air or gas after traversing the por- .tions of the heater pipes Within the purifying section of the Hue of course then passes through to the concentrating section of the Hue and agitates the acid therein as hereinbefore described, the acid being heated and concentrated at from 400 to 450 degrees F., the gases after leaving the acid in the con- -centrating section of the Hue then passing up through the tower in contact with and countercurrent to the down-coming acid, so that the latter after passing into the acid Hue is in a heated condition and susceptible of ready concentration. .After the acid has been thoroughly concentrated and purified, it is Withdrawn from the Hue at the discharge or draw-off pipe 21.

While We have herein shown and described the preferred form of our apparatus, We Wish it to be understood that we do not confine ourselves to all the precise details set forth herein by Way of illustration, as modification and Variation may be made Without departing from the spirit'of thel invention or exceeding the scope of the appended claims.' For example it will be readily understood that we may employ any number of heater pipes in the acid Hue, and that the heating medium may be conducted v to these pipes through any suitable arrangement of connections to meet the particular condition or location of the plant. Furthermore, the baffle or partition Wall may be ara ranged at any desired point Within the Hue so as to 'provide any portions or sections of the desired size'. By providing the ports in the portions ofthe heater pipes lying Within the purifying section of the Hue, with 'c'losures in 'the'.A nature of removable caps or seals, we make provision for opening and closing one or more of the ports as maybe deemed necessary or desirable to regulate the portions of the pipes which can be used as heat' exchangers land the portions which shall be used'for agitation and concentrating purposes.

Furthermore, in some instances '1t may be desirable to subject the'acid in the purifying section o the Hue to concentrating action, this taking place simultaneously With" concentration in the concentrating section of 'the Hue. Y, F or example in the concentrating section of the Hue the acid'may be raised to about 62-64 degrees Baume and then permitted to How into the purifying section of the Hue vwhere simultaneously with the puriiai an@ Hcation itis subjectedto heat to concentrate to a stren t-h` of substantially 66 degrees Baume. T us the acid may be concentrated by the same heating elements While in both an agitated and a vstatic condition.

What We claim is:

1. The herein described method yof concenconcentrating the sludge acid by subjecting la. body of theacid to heat at one stage and then purifying the concentrated acid by subjecting the same to'a` higher degree of heat at another stage to eliminate or neutralize impurities. Y

2. The herein described method of concentrating and purifying sludge acids or separated sludge acids which consists in concentrating the sludge acid at one stage by subjecting a body of the sameto heat and agitationand of purifying the concentrated acid by subjecting the same to heat at a second stage to eliminate or neutralize impurities.

3. The herein described method of treating sludge acids or separated sludge acids which comprises subjecting the acid toa sufiicient degree of heat to concentrate the same While said acid is in a state of agitation, and then subjecting said concentratedl through said: acid to agitate and concen` trate the latter; and subsequently internally heating the `concentrated acid While ina static conditionsufiiciently to eliminate or neutralize undesirable impurities.

5. The herein described method of concentrating and purifying sludge acids which Aconsists in first passin'v the wealr acid in countercurrent to heate air or gas to preheat the same, in then concentrating the acid by passing hot air or hot gas through the acid andagitating the same and sub:

sequently purifying the acid by heating the same to raise the acid to sulicient tempera- 'ture to eliminate or neutralize undesirable impurities. y

6.l The herein described method of concentratingy and purifying sludge acid which comprises passing weak acid in countercurrent to heated air or gas to preheat the same, in then agitatin and simultaneously heating the sludge aci perature to concentrate the latter, and subjecting the acid to a relatively higher deat a suiicient tem# gree of heat than used for the concentration l to eliminate or neutralize undesirable impurities.

7."The

hereinl described kmethod of treating acid which comprises subjecting the' acid while in an agitated condition, to heat,A

vdegrees F., to eliminate or neutralize undesirable impurities.

8. The herein described method of treating sludge acid or separated sludge acid which comprises passin hot air or hot gas through the body of acid to concentrate the same, and internally heating the body of concentrated acid with lhot air or hot gas as the heating medium to eliminate or neutralize undesirable impurities.

9. The herein described method of treating acid which comprises internally heating the acid at one stage, by conducting hot air or hot gas under pressure through a conduit passing through the acid, and subjecting said acidto heat and agitation at another stage, by passing the hot airor hot gas through the acid at the last mentioned stage.

l0. The herein described method of concentrating and purifying sludge acid which comprises passing hot air or hot gas through p a body of the sludge acid at a relatively low temperature, and subsequently subjecting the acid to the heating action of hot air or gas at a relatively high temperature.

11. The hereindescribed method of concentrating and purifying acid which comprises passing weak acid in countercurrent against heated air or gas to preheat the acid, then subjecting said preheated acid to the hot air or gas to agitate and 'concentrate the acid, then permitting said acid to assume a substantially static condition, and then heating the static body of acid suiiiciently to eliminate or neutralize undesirable impurities therein.` j

12. As a step in the art of treating sludge acid, containing hydrocarbon impurities, the process of internally heating the acid to bringthe latter to a temperature of at least 540 degrees F., for the purpose of driving off the volatile limpurities and subsequently reducing the hydrocarbon impurities t0 inert carbon whereby a purified body of acid. iS obtained. i

13. As a step in the art of concentrating and purifying acid, the process which comprises concentrating the acid and allowing it to assume a static condition, and -then purifying the 4acid by conducting highly heated gas or air through the static body of acid toeliminate or neutralize impurities therein. v

14. In an apparatus for treating acid, acid compartments comprising anV acid concentrating section, andl an acid purifying section in communication therewith whereby acid may pass from the concentrating section to the purifying section, meansfoninternally heating the acid in the acid purifylng section without agitation, and means for passing a heating and agitating medium through the acid in the concentrating section.

l5. In'an apparatus for treating acid,- a compartment for concentrating acid, a compartment for purifying the acid, and a heating device adapted to conduct a heating medium through the acid in the purifying compartment without agitation and to pass said heating medium under pressure through the acid in the concentrating compartment.

16. The herein described method of concentrating and purifying sludge acids which consists in first concentrating the sludge acid Y by subjecting the same to heat and agitation at one stage and then purifying the same by subjecting the concentrated .sludge acid to a higher degree of heat without agitation at a second stage to eliminate and neutralize impurities. v

17. The herein described method of treating sludge acids or separated sludge acids which consists in subjecting the said sludge acid to heat and agitation at one stage and thereafter subjecting the acid to heat t0 `neutralize or eliminate impurities while the same is in a substantially static condition.

18. The herein described method of treating sludge acids or separated sludge acids which consists in subjecting the sludge acid to heat and agitation at one stage and thereafter subjecting the said acid to a continued treatment of heat at a higher temperature to neutralize 'or .eliminate impurities while the said acid is in a substantially quiescent state.

19. The herein described method of treating sludge acids'or separated sludge acids which consists in internally heating the acid at one stage by conducting hot air or hot gas under pressure through the acid 'withand State of North Carolina, this 10th dayI of September A. D. 1920.

INGENUIN HECHENBLEIKNER. Signed by THOMAS C. OLIVER, at New York city, in the county of New York and State of New York this 13th day of September, A. D. 1920.

' THOMAS O. OLIVER.

-out agitating the same and in subjecting 

